Novel coating composition

ABSTRACT

A coating composition comprising 90-40 % by weight of a liquid polybutadiene having at least 60 % cis-configuration and a number average molecular weight of 500-20000 and 10-60 % by weight of a liquid polypentadiene having at least 70 % trans-configuration and a number average molecular weight of 500-20000.

United States Patent Yaginuma et a1.

NOVEL COATING COMPOSITION Inventors: Hiroshi Yaginuma, Yokohama;

Takashi Suzuki, Yamato; Atutane Kimi, Yokohama, all of Japan Assignee: Nippon Zeon Co. Ltd., Tokyo, Japan Filed: Feb. 25, 1974 Appl, No.: 445,687

Related U.S. Application Data Continuation-impart of Ser. No. 264,466, June 20, 1972, abandoned.

U.S. Cl..... 106/287 R; 260/33.6 UA; 260/94.3; 260/680 B; 260/894 Int. Cl. C081 37/18; CO8f 45/28 Field of Search 260/669 P, 894, 680 B, 260/94.3, 33.6 UA; 106/287 References Cited UNITED STATES PATENTS 7/1956 Hamner 260/23.7 R

Primary ExaminerTheodore Morris Attorney, Agent, or F irmSherman & Shalloway [57] ABSTRACT A coating composition comprising 90-40 by weight of a liquid polybutadiene having at least 60 cisconfiguration and a number average molecular weight of 500-20000 and 10-60 by weight of a liquid polypentadiene having at least 70 trans-configuration and a number average molecular weight of 500-20000.

4 Claims, No Drawings NOVEL COATING COMPOSITION This application is a continuation-in-part of U.S. Ser. No. 264,466 filed June 20, 1972, now abandoned.

This invention relates to a novel coating composition, and more particularly to a coating composition comprising liquid cis-polybutadiene and liquid transpolypentadiene which have been modified.

Paints are usually classified as oils and enamel paints such as air-drying paints and baking paints, and water thinnable paints such as electrodeposition paints. In the past, most of the commercially available oils and enamel paints contained as film-forming material a natural drying oil consisting mainly of glycerides of linoleic acid, linolenic acid, oleic acid, ricinoleic acid, etc. or a stand oil prepared therefrom. Since these paints have defects in their resistance to chemicalsysurface gloss, storage stability, etc. and their quality was not always constant, studies on the use of synthetic oils in place of natural oils as raw materials for paints have been carried on. Lately, with the progress in the development of cis-polybutadiene rubber, liquid cispolybutadiene was obtained and this was found to be very superior as a paint (see U.S. Pat. No. 3,442,675). According to this process, by using cis-polybutadiene having a viscosity at 20C. of 30-30000 centipoises, epoxidized polybutadiene, polybutadiene which has undergone the Diels-Alder addition reaction or polybutadiene to which an unsaturated compound containing a carboxylic acid group and/or a carboxylic anhydride group has been added as film-forming material of paint, a synthetic paint having a high drying speed and superior gloss and color tone can be obtained. This paint, however, had some faults in hardness and impact resistance, and it has been desired to remedy these defects.

Lately, the electrodeposition coating technique has attracted attention and come into practical use, and research on water thinnable paints, centered on electrodeposition paints, has been vigorously carried out. Electrodeposition coating roughly comprises a process for the preparation of a water-soluble resin, an electrodeposition process and a stoving process, and only a combination of these three'processes and the filmforming'material can produce coated articles having a superior coating performance, and if the combination of the film-forming material with even one of the three processes is not appropriate, it becomes difficult to produce useful coated articles. Of them all, the filmforming material and the process for the preparation of a water-soluble resin, and the film-forming material and the electrodeposition process, have an inseparable relationship, and this has been recognized widely among those skilled in the art.

The substances hitherto used as film-forming material contain an acid group which-is neutralized with bases to be dispersible or soluble in water. Typical examples are maleic linseed oil, maleic dehydrated castor oil, fumaric tung oil, maleic acid-modified hydroxypolybutadiene having a hydroxyl group at the end of or in the molecular chain, maleic acid-modified polybutadiene containing 1,2-bonds of not less than 80 but since all of them lack adaptability to the process for the preparation of a water-soluble resin and/or the electrodeposition process, none of them give satisfactory coating performance.

The present inventors first attempted to use as the film-forming material of water thinnable paint liquid cis-polybutadiene which had been used as an air-drying paint having superior resistance to solvents and water, but no satisfactory result could be obtained, gel formation occurred conspicuously as side reaction in the process for the preparation of a water-soluble resin, and a certain defect in throwing power was caused in the electrodeposition process.

After further ardent studies on' improving the synthetic paint prepared from liquid cis-polybutadiene, however, it was discovered that the above defects can be eliminated by blending liquid cis-polybutadiene with liquid trans-polypentadiene without impairing the merits of cis-vpolybutadiene, and this discovery led to the present invention.

The principal object of the present invention is to provide a synthetic coating composition having superior surface gloss, impact resistance, resistance to water and solvents and hardness and a high drying speed. Another object of the present invention is to provide an improved water thinnable coating composition for which the synthesis of water soluble resin can easily be carried out and which has superior electrodeposition characteristics and coating film performance.

According to the present invention, a composition which contains as film-forming material a mixture comprising 90-40 by weight of polybutadiene having at least 60 of cis-configuration and a number average molecular weight of 500-20000 and. 10-60 by weight of polypentadiene having at least 70 of transconfiguration and a number average molecular weight of 500-20000, and an aqueous composition which contains as the film-forming material a product obtained by making the above mixture water-soluble in the conventional manner, are provided as paint compositions thereby realizing the foregoing objects.

The cis-polybutadiene used in the present invention contains at least 60 of cis-configuration and has a number average molecular weight of 500-20000, preferably 1000-10000, and is usually produced by polymerizing butadiene in the presence of-a Ziegler catalyst consisting essentially of an organoaluminum halide and a nickel compound (see, for example, specifications of U.S. Pat. No. 3,329,734 and Japanese Patent Publication No. 20495/71), but the process for its preparation is not limited to such process. If the cis-configuration is less than 60 the resultant paint has poor drying property, and if the number average molecular weight is less than 500, the drying property becomes poor and the coating film is liable to cause shrinkage, and there is no practical means for preventing it. On the other hand, if the number average molecular weight exceeds 20000, its viscosity increases and it is easily gelled upon heating, and as a result it can not be put to practical use as a paint. Especially when it is used for a water thinnable paint, it is preferable to make its number average molecular weight not more than 5000, preferably not more than 3000 from the view-point of preventing gel formation in the synthesis of the water soluble resin.

The trans-polypentadieneused is a liquid polymer containing at least 70 of trans-configuration and having a number average molecular weight of 500-20000, preferably 1000-10000. This can easily be prepared by polymerizing l,3-pentadiene in a homogeneous system using a Friedel-Crafts catalyst such as solubilized aluminum chloride, boron trifluoride, or a complex thereof, tin tetrachloride, organoaluminum dihalide or sulphuric acid. The use of liquid transpolybutadiene (-U.S. Pat. No. 3,205,2l4) obtained by polymerization vent resistance. Further, trans-polypentadiene copolymerized with a small amount of other olefins such as butene-l,2-methylbutene-2, butadiene and isoprene may also be used in the present invention. The reason why the trans-configuration content is limited is that if it is less than 70 hardness is not improved and the throwing power as an electrodeposition paint decreases. The reason why the molecular weight is limited is the same as that set forth for the case of cispolybutadiene. In case it is used for water thinnable paints, it is preferable to make the number average molecular weight not more than 5000, preferably not more than 3000, for the prevention of decrease of water-solubility.

In the present invention, the mixing ratio of polybutadiene to polypentadiene is one of the important technical means constituting the invention, and superior effects can be obtained only when 90-40 by weight, preferably 80-60 by weight, of polybutadiene and -60 by weight, preferably -40 by weight, of polypentadiene are used. If the amount of polypentadiene exceeds 60 by weight, the flexibility, impact resistance, resistance to water and solvents, etc. of the product become poor, and if it is less than 10 by weight, neither hardness nor impact resistance can be improved. Further when it is less than 10 by weight, there is a defect that gel formation occurs when an unsaturated acid such as maleic anhydride is added to the polymer to make it water soluble. Moreover, the water thinnable paint thus prepared exhibits poor electrodeposition characteristics such as water spotting, throwing power and performance of the coating film.

Since the polymers used in the present invention are both liquid polymers, they can easily be blended together, and, if desired, the blend may be modified by known means before use. For example, adhesive strength can be increased by epoxidizing l-50 preferably 5-20 of the double bonds of the polymers according to known procedure, and a self-fireextinguishing film can be obtained by reacting the blend with hexachlorocyclopentadiene according to the Diels-Alder addition reaction. Further, an unsaturated compound containing a carboxylic acid group and/or a carboxylic acid anhydride group may be attached to the polymers according to a known procedure, and when the additive has an acid value of l-200, the strength of bonding to the coated surface, pigmentwetting property and affinity for compounds having a polar group of the coating composition can be im- 1 proved. Further, the polymer containing a carboxylic acid group and/or a carboxylic acid anhydride group may be blended with a compound having afunctional group, suchas acid amide group, an amine group, an isocyanate group or a hydroxyl group, which reacts chemically with the above functional groups, coated on the surface of a substrate and thereafter reacted together.

Further, the polymers of the present invention may be reacted with an unsaturated carboxylic acid or an unsaturated carboxylic anhydride at a temperature of 50-300C., preferably l50-200C., for 5 minutes l0 4 hours, preferably l-"S hours, and thereafter the reaction product can be neutralized with 0.5-1.5 molar equivalents of an inorganic alkali, an alkali salt or an amineto make it soluble or dispersible in water. The

' and resistance to solvents.

unsaturated carboxylic acid or unsaturated carboxylic acid anhydride is used in an amount of 5-100 parts by weight per lO0'parts by weight of the polymer, and a minimum amount is usually that required'for making the reaction product water-soluble by neutralization. It is'preferable to'carry out the reaction after polybutadiene is blended with polypentadiene, and thereby the gelation of polybutadiene is remarkably restrained. At

the time of reaction, an anti gelling agent such as tertiary-amyl hydroquinone, hydroquinone, diphenylamine, 2,6-ditertiarybutyl-4-methylphenol or a copper compound may be used in an amount of 001-5 by weight based on'the polymer, if necessary. The unsaturated carboxylic acid or unsaturated carboxylic acidanhydride used may be any known compound, and for example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, citraconic acid, fumaric acid and other a,B-unsaturated carboxylic acids, and maleic anhydride, citraconic anhydride may be mentioned, but from the viewpoint of quality and economy, maleic acid anhydride is preferably used. At this time, a catalyst for accelerating the reaction may also be used, if necessary, for example, a radical generating agent which decomposes at a temperature below thev reaction temperature such as ditertiary-butyl peroxide, lauroyl peroxide, benzoyl peroxide, tertiary-butyl hydroperoxide, peroxylauric acid or perbenzoic acid may be used. Further, to decrease the viscosity and make the reaction smooth, a solvent inert in the reaction such as benzene or toluene may be used as diluent. As the amine to be used to neutralize the reaction product, widely known amines such as ethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, diethylamino ethanol, trimethylamine, N-methylmorpholine, 2-amino-2-methyl-l-propanol, 2-amino-2-methyl-lpropanol, 2-amino-2-methyl-l ,3-propanediol and tris(- hydroxymethyl)aminomethane may be mentioned. Alkalies such as ammonia water, caustic soda and caustic potash, and alkali salts such as ammonium carbonate, sodium carbonate and potassium carbonate may also be used for the neutralization. The water-soluble or -dispersible product thus obtained is usually used as a water thinnable paint after its aqueous solution or dispersion having a concentration of 10-25 by weight is prepared, and its pH is adjusted to about 7.5-8.5.

The coating composition of the present invention may also be diluted with a conventional diluent to use it as common paint. A pigment, a filler, etc. may be added as desired, when the composition is used as oil and enamel paint or water thinnable paint. The oil and enamel paint thus prepared shows superior drying property, and can be used widely as a paint having superior hardness, impact resistance, resistance to solvents and waterproofness. The electrodeposition coating film formed by this water thinnable paint shows, after drying superior gloss, flexibility, impact resistance, Ericksen durability test value,

The following Referential Examples and Examples are given for the purpose of illustrating the present invention in more detail. Parts here means parts by weight, unless otherwise specified. In each Table, the

waterproofness 6 marks 0, A and X mean good, ordinary and poor", respectively. 1 Sample F REFERENTIAL EXAMPLE 1 a Number average molecular weight 2500 By polymerizing l,3-butadiene m butene-l as a'sol- 5 Molecular structure Cis-form 7!) 10.2 vent using a catalyst composed of dtethylalumtnum Transient] W 89 1 chloride, nickel naphthenate and water, samples of liqvin'yHOm; 7 ()5 uid polybutadiene having the below-mentioned properties were prepared.

7 EXAMPLE 1 Sample A B C Number average The cis-polybutadiene (sample B) having a number molecular weight 1600 3300 9 1 average molecular weight of 3200 prepared in Referen-v Molecular structure cis form (76) 790 839 901 tial Example 1 was blended with the polypentadiene Trans-form 19.9 14.2 (sample D) having a number average molecular weight Y U of 1500 prepared in Referential Example 2 at the ratios shown in Table l, and then 40 parts of this blend were I REFERENTIAL EXAMPLE 2 blended with 60 parts of rutile type titanium white. The By polymerizing 1,3-pentadiene using boron trifluoresultant blend was dispersed for 2.5 hours in a ball ride ethyl etherate as the catalyst, samples of liquid mill, and after it was confirmed by a particle gauge that polypentadiene having the below-mentioned properties the par ic es were 1658 than 10 microns in Size, the were prepared blend was brush-coated once in an amount of 1 g/dm After the coating was baked for minutes in' a hot Sam le blast-circulating oven heated at 180C, the resultant D E film was tested according to JIS-K-5400. For comparison, commercial liquid 1,2-polybutadiene (number av- Number average "mlecular 1500 6300 erage molecular weight 2140, 1,2-configuration 9l.2 Molecular structure (17) 8.0 65 30 product of Nippon Soda Co., Ltd.) was, put to the Trans-form (7r) 90.0 91.0 a t t Y 7 vmyl form (7) .The results were as shown tn Table l.

Table l r Run No Examples of the present Control invention Control Sample B (parts) 100 90 70 3o Sample D (parts) 1o 30 59 70 100 Liquid l,2-polybutadicne (parts) l00 Appearance (smoothness and gloss) O O O O X X 0 Flexibility test (cylindrical) mandrel apparatus) (4 mm) 0 O O O X X X Flexibility test (cylindrical) mandrel apparatus)(2 mm) X 0 O O X X X Pencil hardness B H8 H8 H8 H H H Cross cut value 70 80 70 7O 50 50 '80 Du Pont impact resistance *1 X 0 O O X X X Ericksen value (mm) 7.2 7.7 8.6 8.0 4.0 could not be 2.0

Y measured Water resistance *2 O O i O O X X O Solvent resistance *3 O O O X X 0 Anti-corrosiveness Rust Rust N0 Rust Rust Rust Rust (salt water spraying) spots spots :rreguspots spots spots spots antles l Du Pont impact resistance: A inch X 500 g X 50 cm. "2 Water resistance: Immersed in water at 20C. for 3 days. 3 Solvent resistance: lmmersed in No. 2 naphtha at 20C. lur 2 days.

REFERENTIAL EXAMPLE 3 By polymerizing l,3 -pentadiene in benzene as a solvent using a catalyst composed of triethylaluminum and titanium tetraiodide (Al/Ti molarv rati v sample of liquid polypentadiene having thefbelowmentioned properties was prepared.

f2.4 a terial.

EXAMPLE 2 I The polybutadiene (sample C) having a number av- 7; erage molecular weight of 5700 prepared in Referential Example 1 was blended with the polybutadiene (sample D) having a number average molecular weight of 1500 prepared in Referential Example 2 at the ratios shown in Table 2, and then 1.0 part, as lead, of lead naphthenate and 0.1 part, as nickel, of nickel naphthenate were added to 100 parts of the blend and the mixture was blended adequately. The resultant paint composition was coated on a clean test piece of glass or tin-plate to a thickness of 1 mil (l/l000 inch) with a doctor knife, the coated film was allowed to stand at a temperature of 20C. and a relative humidity of 75 7(, and its drying property was tested at regular intervals of time. After the film hardened, it was further allowed to stand for a week, and was tested according to JlS-K- 5400. The results were as shown in Table 2. z I

From-the above results, i t, is found that the paint of the present invention is superior in flexibility hardness, du Pont impact resistance and Ericksen durability test value as compared with the paint using cispolybutadiene as the film-forming material.

I H EXAMPLE 4 The polybutadiene (SampleA) having a number average molecular weight of l600 prepared in Referential Example 1, the polypentadiene (Sample D) having a number average molecular weight of 1500 prepared in Referential Example 2, linseed oil and liquid 1,2- polybutadiene (number average molecular weight 2140, l,2-bond content 912 product of Nippon- Soda Co., Ltd.) were blended'together at the ratios shown in Table 4. A glass container providedwith a Table 2 v Run No. 5 Examples of the present Control invention Control 8 H 9 10 ll l2 13 Sample C (parts) 100 90 70 5o Sample D (parts) 10 30 50 70 100 Drying time Set to touch (hrs) 0.5 0.5 0.5 O.75 2.0 2.0 Semi-cured (hrs) 0.7S 0.75 0.75 10 4.0 4.0 Cured (hrs) 18 18 18 18- 48 72 Flexibility test (cylindrical mandrel apparatus) 4 mm m diameter O O O O X X 2 mm in diameter X A O A X X Y Y Pencil hardness 6B 2B 8 H 2B 3B Cross cut value 50 50 50 30 20 lmpaet resistance test (du Pont) X 0 O O X X Ericksen value (mm) 9.0 9.4 10.0 9.0 8.2 3.4 Water 0 O O O X -X Solvent resistance 0 O O O X X A Anti-eorrosiveness Rust Rust No irre- Rust Rust Rust (salt water spraying) spots spots gularities spots spots spots From the above results, it is found that the paint of the present invention has a drying property equivalent to that of the paint using cis-polybutadieneas the filmforming material.

EXAMPLE 3 The polybutadine (Sample B) having a number average molecular weight of 3200 prepared in Referential Example 1 was blended with the polypentadiene (Sample E) having a number average molecular weight of 6300 prepared in Referential Example 2 at the ratios shown in Table 3, and this blend was further blended with lead naphthenate and nickel naphthenate of the same recipe as in Example 2. The resultant paint composition was coated on a substrate in the same manner as in Example 2, and the film was tested according to JlS-k-5400. The results were as shown in Table 3.

thermometer, a stirrer, a reflux condenser and a conduit for letting a gas in was charged with 100 parts of the polymer blend and 20 parts of maleic anhydride, and then purged with gaseous nitrogen. While passing gaseous nitrogen thereinto, the contents were heated to 60C. to melt maleic anh y'dride." After maleic anhydride was melted,.the contents were heated to 200C. with stirring, and the reaction was continued at 200C. for 4 hours. A small amount of sample was taken out of the reactor, and put to a spot color reaction test to ascertain if any maleic anhydride remained. The result was negative except in the case of Run No. 24 where 1,2- polybutadiene used. The solubility of the sample in butyl cellosolve, toluene and carbon tetrachloride was examined to confirm if any gel formation had occurred. After this test, the contents were cooled, and when the internaltemperature lowered to about 60C., 15 parts of-butyl cellosolve were added to 85 parts of the contents from which gel, if any, had been removed, and after mixing them well, the acid value of the blend was measured. 0.8 equivalent, based on this acid value, of triethanolamine was added thereto, and mixed well. By adding ion exchange-purified water thereto, a water soluble, thermoset'ting resin'composition"having a resin content of 20 was produced. After the composition was allowed to stand overnight, its water-insoluble gel was removed through a m esh wire gauge, its solids content was measured, ain'd the calculatedamount of pure waiter-was added'jliereto to adjust thCfSOlldS contentat Its pl-l value was measured, and it was foundth'at the value fell withinthe range of 7.5" 8.5. Using this-liquid, an electrodepositidn test wasconducted under the following conditions.

Electrodeposition at constant voltage: 80 volts.

Time of deposition: 2 minutes.

Distance between cathode and anode: 7 cm.

Anode surface area: 195 cm (0.8mm X 65 mm X 150 mm phosphoric acid-treated iron plate).

Stirring: Done.

Bath temperature: 25C.

After passage of electricity was discontinued, the test piece thus electropainted was taken out, powerful water spray was applied to the coating film surface to remove the adhering electrodeposition liquid, and then the test piece was air-dried for 3 hours in a chamber at a temperature of 25C. and a relative humidity of 75 Thereafter, its water spotting was judged. Then, the airdried test piece was placed in a hot blast-circulating oven at 180C. for 30 minutes to cure the coating film, which was put to a coating film performance test according to .llS-K-5400. The results were as shown in Table 4.

amples of the present invention, gel formation does not occur, and films of superior washability, spotting and throwing power are obtained. Since maleinized 1,2- polybutadiene having a number average molecular weight of 2140 gives very inferior washability when treated under the same conditions, this is not fit for practical use, and linseed oil gives inferior results with respect to throwing power and impact resistance. The films of the present invention generally show superior properties such as gloss, smoothness, flexibility, pencil hardness, impact resistance and water resistance and solvent resistance. 5

EXAMPLE 5 The polybutadiene (Sample B) having a number average molecular weight of 3200 prepared in Referential Example 1 was blended with the polyp'entadiene (Sample D) having a number average molecular weight of Table 4- 1) Run No. Examples of the Control present invention Control l7 l8 19 20 21 22 23 24 Sample A (parts) 100 90 70 so Sample D (parts) I0 30 100 Linseed oil (pans) 100 Liquid 1,2-polybutadiene (parts) lOt) Gelation in maleinization reaction Butyl cellosolve Not Dis- Dis- Dis- Dis- Dis- Dis- Dis- 1 dissolved solved solved solved solved solved solved solved Toluene v I, 7 1 I, I, H H H Carbon tetrachloride Acidvalue (mg-KOH/g-polymer) I 35' 88 90 92 95 95 95 42 Electrodeposition characteristics Washability Excel- Excel- Excel- Excel- Excel- Good Very lent lent lent lent lent bad Water spotting Good Good Good Good Good Good Water spots Throwing power (7:) 80 100 100 100 80 50' Table 4(2) Run No. Examples of the Control present invention Control Properties of deposited film Smoothness and gloss Excel- Excel- Excel- Bad Bad Good Very bad lent lent lent Film thickness s) 25 25 25 l5 I0 25 15 Flexibility (100 mm) O O O X X 0 X Flexibility (2 mm) O O O X X 0 X Pencil hardness HB HB HB HB HB HB H Cross cut value 90 100 I00 lOO 80 90 90 Impact resistance test (du Pont) (W' X 1000 g X 50 cm) O O O X X X X Ericksen value (mm) 7.2 10.0 9.6 4.] 2.9 7.2 4.5 Water resistance O O O X X 0 O Solvent resistance 0 0 O O A X X X Antl-corrossiveness Rust Good Good Rust Rust Good Good (salt water spraying) spots spots spots l500 prepared in Referential Example 2 at the ratios shown in Table 5, and then subjected to the same procedure as in Example 4. The electrodeposition charac* teristics and the properties of the deposited film were examined. The results were as shown in Table 5.

On comparing Run No. 26 (Table 5) with Run No. 18 (Table 4), it is found that as the molecular weight of cis-polybutadiene becomes larger, the tendency of gel formation in the maleinization reaction becomes 11 v stronger. Excellent" balance among pencil hardness, du Pont impact resistance and Ericksen value means that all these properties are superior to those of conventionally used electropainting compositions.

lt is apparent from the foregoing results that the use of the trans-polypentadiene (sample F) polymerized by using a Ziegler-typecatalyst affords a paint having very slow drying speeds and inferior coating properties. On

Table 5 Run No.

Control Examples of the present invention Control 26 l 27 t 2x 29 Sample B (parts) [00 90 70 50 Sample D (parts) I l0 30 I00 I Geletion in maleinization reaction .Recogni- Not Not Not Hardly zable recognirecognirecognirecognig Y zahle zahle zable zable Electrodeposition characteristics Good Good Good Good Condition of deposited film Good Excellent Excellent Bad Film Thickness 20 25 25 I0 Balance among pencil hardness. du Pont impact resistance and Excellent Excellent Excellent Bad Ericksen value EXAMPLE 6 the other hand, the paint of the present invention which The polybutadiene (Sample C) having a number average molecular weight of 5700 prepared in Referential Example 1, the polypentadiene (Sample D) havinga number average molecular weight of 1500 prepared in Referential Example 2 and the polypentadiene (Sample F) having a number average molecular weight of 2500 uses the trans-polypentadiene (sample D) polymerized by, using a Friedel-Crafts catalyst, features fast drying and superior coatingproperties.

What we claim is: I

'1. A coating composition comprising 90-40 by weight of liquid polybutadiene having at least eis- P p in Referemifll Example 3 were blended '30 configuration and a number average moleculan Weight gether at the ratios shown In Table 6, and then 1.0 part. of 50 2 0 0 and 6() by i h f li id l as lead, of lead naphthenate and 0.] part, as nickel, of pentadiene prepared by polymerizing l,3 pemadiene in nickel naphthenlte were added 100 Parts of the a homogeneous system using a Friedel-Crafts catalyst blend and -f was blelfd'ed adequately 4 having at least trans-configuration and a number The resulting paint composition was coated on a 35 averagg molecular weight of 500 20O0O clean test piece of glass or 'tin plate to a thickness of l mill (1/100 inch) with a doctor knife, the coating film 2. -A coating composition comprising 60 by was allowed to stand at a temperature of 20C. and a weight of liquid polybutadiene having at least 60 cisrelative humidity of 75 and its drying property was configuration and a number average molecular weight tested at regular intervals of time. After having hard- 40 of 500-20000 and 20-40 by weight of liquid polyened, the film was further allowed to stand for a week, pentadiene preparedby polymerizing l,3pentadiene in and was tested according to S K-5400. The results a homogeneous system using a Friedel-Crafts catalyst were as shown in Table 6. having at least 70 trans-configuration and a number Table 6 Run No.

Example of Control the present Control invention 30 3l 32 33 34 Sample C (parts) I00 70 70 Sample D (parts) 30 Sample F (parts) 30 I00 Drying time Set to touch (hrs) 0.5 0.5 4.0 2.0 8.0 Semi-cured (hrs) 0.75 0.75 l8 4.0 48 Cured (hrs) 18 18 72 72 over 240 Flexibility test Cylindrical mandrel appas. 4 mm in diameter 0 O O X 0 2 mm in diameter. X 0 AX X Pencil hardness 68 B 68 3B 5B Cross-cut value 40 S0 40 20' v 30 lmpactresistance test X X X X4 Ericksen value'(mm) 9.0 10.0 8.5 3.4 8.2 Water resistance 0 O X X 1 X Solvent resistance O O X X X Anti-corrosiveness Rust No Rust Rust, Rust spots I irregularispots spots spots average molecular weight of 500-20000.

3. A coating composition comprising 90-40 by weight of liquid polybutadiene having at least 60 cisconfiguration and a number average molecular weight of 1000-10000 and -60 by weight of liquid polypentadiene prepared by polymerizing 1,3-pentadiene in a homogeneous system using a Friedel-Crafts catalyst having at least 70 trans-configuration and a number average molecular weight of 1000-10000.

Patent 3,897,260 Dated July 29. 1975 Inven tor 3 R SHI YAGINUMA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, insert the following priority imformation:

--Claims priority applications, Japan, June 25, 1971,

45743/71: June 25, 1971, 45744/71-- Signed and Scaled this fourteenth D ay Of October 19 75 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ofPatents and Trademarks 

1. A COATING COMPOSITION COMPRISING 90-40 % BY WEIGHT OF LIQUID POLYBUTADIENE HAVING AT LEAST 60% CIS-CONFIGURATION AND A NUMBER AVERAGE MOLECULAR WEIGHT OF 500-20000 AND 10-60 % BY WEIGHT OF LIQUID POLYPENTADIENE PREPARED BY POLYMERIZING 1,3-PENTADIENE IN A HOMOGENEOUS SYSTEM USING A FRIEDEL-CRAFTS CATALYST HAVING AT LEAST 70 % TRANS-CONFIGURATION AND A NUMBER AVERAGE MOLECULAR WEIGHT OF 500-20000.
 2. A coating composition comprising 80-60 % by weight of liquid polybutadiene having at least 60 % cis-configuration and a number average molecular weight of 500-20000 and 20-40 % by weight of liquid polypentadiene prepared by polymerizing 1,3-pentadiene in a homogeneous system using a Friedel-Crafts catalyst having at least 70 % trans-configuration and a number average molecular weight of 500-20000.
 3. A coating composition comprising 90-40 % by weight of liquid polybutadiene having at least 60 % cis-configuration and a number average molecular weight of 1000-10000 and 10-60 % by weight of liquid polypentadiene prepared by polymerizing 1,3-pentadiene in a homogeneous system using a Friedel-Crafts catalyst having at least 70 % trans-configuration and a number average molecular weight of 1000-10000.
 4. A coating composition comprising 80-60 % by weight of liquid polybutadiene having at least 60 % cis-configuration and a number average molecular weight of 1000-10000 and 20-40 % by weight of liquid polypentadiene prepared by polymerizing 1,3-pentadiene in a homogeneous system using a Friedel-Crafts catalyst having at least 70 % trans-configuration and a number average molecular weight of 1000-10000. 